@
lazorbeam - sorry, I only tested deleting a file, when I saw that worked I assumed adding and renaming would work - because I assumed the PI built the list from the directory when it runs - alas it doesn't.  It keeps a list of them in its .json file in the plugins directory a'la:- 
	Code:
	  "Files": [
    "Draghi's Dungeons.jpg", 
    "Bank Of England.jpg", 
    "Brunhilde_the_Valkyrie.jpg", 
    "Ekaterina Motyakina .jpg", 
    "Kris Swindle.jpg", 
    "Linen Cover 10.jpg", 
    "{Current Cover}", 
    "{Default Image}"
  ]
 Note the double quotes and trailing comma's, they are essential.
BR